Heating, hot water and electricity are one of the three big areas of a personal footprint, with travel and food. The good news is that the biggest home changes are one-off decisions: once you switch supplier or insulate, the savings repeat every year without further effort.
This page is part of our guide to reducing your carbon footprint, in the carbon footprint section. To see how large your home energy is compared with travel and food, run the carbon footprint calculator first.
Which home changes save the most?
A 2020 review of 53 studies compared consumption options by how much CO₂e they save per person a yearSource 1. In the housing domain, the results were:
Scrolls sideways to show every column.
| Change | Saving (t CO₂e per person a year) | Basis |
|---|---|---|
| Buy renewable electricity | 1.6 | Median |
| Refurbish and renovate | 0.9 | Median |
| Switch to a heat pump | 0.8 | Average |
| Switch to renewable-based heating | 0.7 | Average |
| Generate your own renewable electricity | 0.6 | Median |
| Move to a passive house | 0.5 | Average |
| Less living space or co-housing | 0.3 | Average |
| Save hot water | 0.3 | Average |
| Smart metering | 0.2 | Average |
| Lower room temperature by 1–3°C | 0.1 | Average |
As of Oct 2026 · Source: [1] Ivanova et al., Environmental Research Letters 2020
The authors stress that results depend on context: the energy source being replaced, the local climate, the type of dwelling and how much of the local grid is already renewableSource 1. A household with an oil boiler in a cold climate has more to gain than one in a mild climate with a clean grid.
Switch to renewable electricity
Buying renewable electricity had the highest median saving in the housing domain, at 1.6 tonnes of CO₂e per person a yearSource 1. Producing your own, for example with rooftop solar, had a median of 0.6 tonnes, with a very wide range between studiesSource 1.
Your grid matters. Electricity factors vary a lot between countries; Our World in Data publishes the carbon intensity of each country’s electricity, from EmberSource 4. On a cleaner grid, switching supplier saves less, and electrifying heating saves more.
Heat your home with less carbon
Heating is where renovation pays off. The review found average savings of 0.9 tonnes for refurbishment and renovation, 0.8 tonnes for a heat pump and 0.7 tonnes for renewable-based heatingSource 1. The IPCC found that, in developed countries, the largest mitigation potential in buildings lies in retrofitting existing buildingsSource 2.
Why does electric heating help? In the UK, a kWh of grid electricity now carries a lower emission factor than a kWh of gas: about 0.144 kg CO₂e including transmission losses, against 0.182 kgSource 3.
Step 1: Stop the heat escaping
Loft and wall insulation, draught-proofing and better windows reduce the heat you need before you change how you make it.
Step 2: Replace the boiler when it is due
Plan a heat pump or other low-carbon system before your old boiler fails, so you are not forced into a like-for-like swap.
Step 3: Run the system well
Lower flow temperatures, timers and zoning get more from whatever system you have.
Everyday habits
Habits help, but by less than the changes above. In the review, saving hot water averaged 0.3 tonnes of CO₂e per person a year, smart metering 0.2 tonnes and lowering room temperature by 1–3°C 0.1 tonnesSource 1. Smart meters work mostly by making energy use visible, which can prompt bigger changes such as retrofittingSource 1.
- Shorter, cooler showers cut the energy for hot water.
- Wash clothes at lower temperatures and air-dry where you can.
- Turn the heating down a degree or two, and heat the rooms you use.
- Replace old appliances when they fail with efficient ones, rather than early.
The IPCC lists adaptive heating and cooling choices and building-integrated renewable energy among the low-carbon options people can adoptSource 2.
Do the one-off jobs first
A tariff switch takes an afternoon and saves more than years of turning lights off. Make the one-off changes first, then build habits around them.
Space and sharing
How much space you heat matters. Less living space and co-housing, such as a smaller home, living with others or renting out a spare room, saved an average of 0.3 tonnes and up to 1.0 tonne of CO₂e per person a yearSource 1. People who live together share heating, lighting and appliances. The authors note real barriers to downsizing, from a lack of alternatives to attachment to a homeSource 1.
What if you rent?
Renovation, heat pumps and rooftop solar are usually the owner’s decision. Renters still have options:
- Choose your electricity tariff if the bill is in your name.
- Ask your landlord about insulation and heating upgrades, and point to the savings on the bills.
- Use portable fixes such as draught excluders, thick curtains and radiator reflectors.
- Build the habits above, which work in any home.
How much could buildings cut?
At global scale, the IPCC found that up to 61% of building emissions could be mitigated by 2050. Energy efficiency policies make up 42% of that potential, sufficiency policies that avoid demand for energy and materials 10%, and renewable energy policies 9%Source 2.
Next steps
Home energy is one part of the picture. Compare it with travel and food, which often matter as much. Once you have made the changes you can, reduce vs offset explains where carbon credits fit for what is left.